Continuous winder system and method



May 7, 1968 J. D. VAWTER CONTINUOUS WINDER SYSTEM AND METHOD Filed July6,. 1956 INVENTOR.

.MIESOA/ WIM/IFR 4 Tram/ys United States Patent O 3,381,459 CNTiNUOUSWINDER SYSTEM AND METHGD Jamieson D. Vawter, Monterey Park, Calif.,assignor to Spectrol Electronics Corporation, City of Industry, Calif.,a corporation of Delaware Filed July 6, 1966, Ser. No. 563,104 lt)Claims. (Cl. 5718) ABSTRACT F THE DSCLSURE Electrical conductor isunwound from a supply spool onto a mandrel fed axially through saidspool by means of a driven winding cage that includes contacts adjacentthe unwinding path of the conductor which are electrically connected toa motor to reciprocate said spool axially relative to said winding cageto maintain the unwinding angle substantially constant.

rl`his invention relates generally to improved apparatus and methods forwinding a coil of strand material upon a continuous core mandrel.

Although the present invention nds particularly useful application inthe iield of machinery and techniques for producing wire wound coils,resistors, and the like for electrical elements and components, andalthough in the cause of brevity and clarity, much of the followingdiscussion of an example of the invention is directed theretoward, it isexpressly to be understood that the advantages of the invention areequally well manifest in other fields wherein it is desired to wrap orwind, at high speed and with precision, a continuous core element withstrand material.

In the field of providing such electrical devices which include a coilof strand material, such as insulated or noninsulated conductive(including resistive) wire, wound over a mandrel to form, for example, aresistance element as for a variable resistor, it is highly desirable,for precision repeatability between ditlerent components as well as fortheir economic mass production, that the coils be continuously Woundover a very long or continuous mandrel. The long coil is then partedinto the desired individual, wire wound components. With such a generaltechnique, it is possible in accordance with the features of the presentinvention to manufacture, at very high speed, resistance elements havingprecisely constant parameters, and therefore electrical resistancecharacteristics, over their entire lengths. Thusly to wind a coilcontinuously over a mandrel requires, however, either that the mandrelbe rotated while a source of strand material, such as a spool ofresistance Wire, is moved, relatively, along the length of the mandrelin a manner to create and control the winding pitch while maintaining apredetermined tension in the wire, or that the winding mechanism itself,including the spool of source, be rotated around the mandrel while oneor the other is translated longitudinally to provide the pitch in theresultant winding.

Attempts in the past to achieve such continuous winding have typicallybeen directed toward a lathe-type machine which spins the mandrel as aworkpiece and carries a spool of resist-ance wire on the tool-holdercarriage at a xed longitudinal rate with respect to the angular velocityof the mandrel to determine thereby the pitch of the coil. Suchtechniques can be made to provide relatively precise components.

The lathe-type winding process cannot, however, be a truly continuousone unless a source of the mandrel material is also being spun; andmeans is provided for axially moving the mandrel past the spool ofresistance wire. Furthermore, as a practical matter, such techniques canprovide a length of coil which is no longer than the per- 3,381,459Patented May 7, 1968 ice missible travel of the tool holder carriagealong the bed of the machine. A further disadvantage of spinningmandrel-type machines is that at usefully high speeds of operation thereis always some lateral flipping of the spinning elongated mandrel whichdeleteriously varies the tension in the winding wire, and consequentlythe diameter or pitch, or both, of the resultant coil.

Other typical prior art attempts to achieve continuous coil winding havebeen directed toward the development of machines in which the mandrel isrotationally stationary while a winding mechanism carrying the spool ofresistance wire is rotated thereabout. The mandrel may in such cases betruly continuously fed past the winding mechanism. However, the requiredcentripetal forces for the revolving winding mechanism even whendynamically balanced, generally limit the process to a relatively lowspeed. Typically in such systems, the reservoir spool of resistance wireis made to have a small diameter so that the system may have a minimumeffective moment of rotational inertia and will require a minimum ofcentripetal forces to hold the mechanism together. However, thisnecessitates making it longer in order to provide it with a practicalcapacity for the strand material.

Making the spool longer seriously aggravates another problem in thistype of machine', namely, that of removing the strands from the spool athigh speeds. There must effectively be a single output point for thestrand to leave the reservoir assembly. This output point generally musthave a fixed axial relationship with respect to the Winding point wherethe strand is applied to the mandrel. As the strand is pulled from thespool and conveyed to the output point, it s pulled from a wide range ofdirections; that is, from the different ends of the spool. This range otdirections is measured by the angles subtended at the output point bythe opposite eliective ends of the spool.

Since the lineal velocity of the strand between the reservoir spool andthe mandrel is constant, and since the distance the strand must travelto arrive at the output point from the spool varies due to the axialmotion of the point of unwinding of the material from along the lengthof the spool, it follows that the angular velocity or the unwindingspool must vary as the point of unwinding moves from one end of thespool to the other. It may be considered that this relative longitudinalmotion of the point of unwinding alternate-'ly adds and subtracts acomponent of velocity to the lineal motion of the strand. The relativemagnitude of this component compared to the total lineal strand velocitydetermines the amplitude of oscillation or variation of the angularvelocity of the unwinding spool and is proportional to the magnitude ofthe range of directions between the spool and the output point; that is,the greater the change 'of direction suffered by the strand in reachingthe output point from various points on the spool, the greater is therequired variation in the rotational velocity of the spool.

This variation in angular unwinding velocity of the strand spool resultsin variations and tension and, consequently, in geometric and electricparameters of the strand as it is wound upon the mandrel. In additionthe same phenomenon may cause fouling in the spool at high speeds.Furthermore, the variation and tension and the longitudinal pulling ofthe strand at the point of unwinding, particularly at points axiallymost remote from the output point, causes additional fouling as adjacentloops of the strand are rolled over each other.

When the output point can be removed radially from the vicinity of thespool the range of angle or direction change of the strand is reduced;however, attempts in the prior art so as to remove the output point haveresulted in increased rotational inertia or unbalance or both.

Another general approach towards solving these problcms has beendirected toward providing a programmed longitudinal oscillation of thespool with respect to the output point, either by moving the spool or bymechanically moving the output point, so that the unwinding pointremains axially fixed with respect to the output point. However, theresultant prior art solutions and mechanisms developed toward that endhave heretofore been either impractically bulky and complex or haveemployed formidably complex programming and controls because, forexample, the frequency of the longitudinal oscillation of the spool mustvary with the varying effective diameter of the unwinding spool, andthese rates of change depend upon the strand size itself.

It is therefore an object of the present invention to provide acontinuous coil Winder machine system and method which are not subjectto these and other disadvantages of the prior art.

It is another object to provide such apparatus in which the mandrel doesnot rotate and may be truly continuous.

It is another object to provide such a coil winding system in which thestrand always leaves the reservoir spool substantially at right anglesthereto.

It is another object to provide such an apparaus in which the outputpoint of the reservoir assembly is at an axially fixed point which isradially contiguous to the spool.

It is another object to provide such a coil winding machine which maywind with high precision and repeatability at angular rates of severalthousands of revolutions per minute without submitting the windingstrand to appreciable tension or to variations therein.

It is another object to provide such a continuous coil winding machinewhich mechanically is simple, rugged and reliable.

Briey, these and other objects and advantages are achieved in accordancewith the structural aspects of an example of the invention whichincludes means for lineally driving a continuous length of mandrel corestock along a given path -at a predetermined velocity. A winding cage isdisposed about the mandrel path and is driven at high angular velocityconccntrically about the core axis. The winding cage includes means forreceiving power at an axially fixed point, the strand to be wound aboutthe core and for feeding the strand to an axially stationary windingpoint adjacent the core. The axial position of the Winding cage may beconsidered to be fixed with respect to a base, supporting structure andis rotatably driven by power means also carried by the base structure.This power means is also coupled to the mandrel lineal drive means toprovide a predetermined desired pitch producing relationship between thelineal drive and the angular velocity of the winding cage.

Also carried by the base structure is a reservoir spool carriage whichsupports a spindle for the reservoir spool. This spool mounted on thecarriage is, in this example, adapted to be disposed within andconcentric with the winding cage.

The winding mechanism is threaded by removing the end of the strand fromthe spool, passing the strand though the receiving means on the windingcage, carrying it through the feeding means to the winding point, andafxing it to the mandrel.

The spool carriage is axially movable and is driven back and forthaxially, in this example, by an electric motor so that the strandunwinding point on the reservoir spool is maintained axially inalignment with the strand receiving means on the winding cage.

The control system for the carriage drive motor cornprises a pair ofclosely spaced wire sensing elements carried by the winding cage at theWire receiving point and between which the strand passes as it is pulledfrom the reservoir spool. The wire sensing elements are axially spacedand positioned so that when the spool unwind point is axially alignedwith the strand receiving means on the winding cage, neither sensingelement is contacted by the wire and there is no energizing currentsupplied through the carriage drive motor. When, however, the spoolunwind point is not aligned with the strand receiving point on thewinding cage, one or the other of the sensing elements is contacted bythe wire and an appropriate signal is generated to cause energization ofthe carriage drive motor in a direction and for a period of time tocause a continually maintained alignment between the spool unwind pointand the winding cage receiving point as sensed continuously by thesensing elements.

By operation automatically of these means, the spool supporting Carriageis driven forth and back in a manner to provide the desired alignment.It may be considered, in this connection, that the motion added to thespool by the carriage drive motor exactly compensates for thatconlponent of the wire velocity, otherwise occurring due to the axialmovement of the spool unwind point.

Further details of these and other novel features of the inventionincluding details of an example of the carriage and its driving motor aswell as an example of the sensing elements briefly described above andtheir principles of operation as well as additional objects andadvantages of the invention will become apparent and be best understoodfrom a consideration of the following description taken in connectionwith the accompanying drawing which is presented by way of anillustrative example only and in which:

FIGURE 1 is a schematic and simplified longitudinally sectioned view ofan example of a continuous coil winding machine system constructed inaccordance with the principles of the present invention;

FIGURE 2 is a sectional view of the sensing element portion of thestructure shown in FIGURE 1 taken along the reference lines Z-Z thereof;

FIGURE 3 is a cross-sectional view of the structure of FIGURE 2 takenalong the reference lines -S thereof; and

FIGURE 4 is a view, like that of FIGURE 3, of a portion of analternative example of the invention.

With specific reference now to the figures in detail, it it stressedthat the particulars shown are by way of example and for purposes ofillustrative example only and are presented in the cause of providingwhat is believed to be the most useful and readily understooddescription of the principles and structural concepts of the invention.In this regard no attempt is made to show structural details of theapparatus in more detail than is necessary for the fundamentalunderstanding of the invention, the description taken with the drawingmaking it apparent to those skilled in the arts of winding and wrappingmachines and systems how the several forms of the invention may beembodied in practice. Specifically the details shown are not to be takenas a limitation upon the scope of the invention which is defined by theappended claims forming, along with the drawing, a part of thisspecification.

In FIGURE 1, the example of the continuous Winder system illustratedincludes a supply 10 of core stock material 12 which is drawn from thesource and through an appropriate mandrel straightener 14 by a linealdrive mechanism 16. The mandrel stock 12 is then moved longitudinallyalong the axis of a winding cage assembly 118, past a winding point 20therewithin, and out of the winding part of the machine at its left handend as shown. To permit the indicated passage of the continuous mandrel,the winding cage assembly is provided with a hollow axial bore ofadequate diameter to clear the mandrel along the entire length ofassembly 18.

Also similarly bored and supported concentrically about the mandrel axisand disposed within, in this example, the open right hand end of thewinding cage assembly 18 is a wire reservoir spool 22 and a spindle 24for the spool. The spindle supports the spool and is, in turn, carriedby a carriage assembly 26. The carriage assembly is provided with alongitudinal freedom of motion and coupled to a lead screw 28 in amanner such that actuation of the lead screw 28 in either of two sensesof rotation causes the carriage assembly and the spool 22 to moveaxially in a corresponding fashion either to the left or right. Thesetwo senses, whether in referring to the lead screw rotation or the axialtranslation of the spool, may be denoted forward and reverserespectively. The forward sense is taken to be that which moves thecarriage assembly in the direction of travel of the mandrel stock.

The lead screw 28 is connected, in this example, to a reversing electricmotor 30. It may be noted that the motor 30, the lead screw 28, itssupporting base 32, and the winding cage assembly 18 are all xed asregards longitudinal movement with respect to a stationary supportstructure, not shown.

The winding cage assembly is rotatably supported by the same stationarysupport through a set of bearings 34. A drive motor 36 also carried bythe stationary support is rotationally drivingly coupled to a gear orpulley member 38 affixed to the winding cage assembly 18.

The drive motor 36 is shown coupled to the lineal drive mechanism 16 toindicate that a desired, predetermined relationship between the angularvelocity of the winding cage and the lineal velocity of the mandrelstock is maintained to provide the desired winding pitch of the strandupon the mandrel stock.

The winding cage assembly 18 includes, in this example, a set of wiredirecting pulleys 40, 42, 43, shown schematically, for directing thewire from an unwind point 44 on the spool 22, to a wire receiving point46 on the winding cage, to the winding point on the mandrel.

As the wire strand 48 is fed from the unwind point 44 to the receivingpoint 46, it passes between a pair of wire contact sensing elements 5t),52. In this example, the sensing elements are polished, conductive postsmounted electrically insulatively on a support member 54 which is inturn carried by the winding cage. The sensing elements 50, 52 are spacedto permit the strand 48 to pass between them without necessarilycontacting either one, and they are disposed axially astraddle of apoint in alignment with the wire receiving point 46. By this means, asdescribed more fully below, the wire strand 48 does not contact eitherof the posts of the sensing elements when the spool unwind and wirereceiving points 44, 46 are in axial alignment. When, however, theunwind point 44 is relatively forward, the post of the sensing element50 is contacted by the wire strand 48; and, conversely, when the unwindpoint 44 is relatively rearward, the post of the sensing element 52 iscontacted.

The sensing element 50 is connected, in this example, through a lead 55to an insulated slip ring 56; and the sensing element 52 is connectedthrough a lead 57 to a slip ring 58. The conductive wire strand 48 iseffectively grounded to the winding cage assembly frame as indicated bythe dashed connection 60. Similarly a third slip ring 62 is grounded tothe winding cage frame as shown.

Each of the slip rings 56, 58 is connected, as by a brush, to a coilterminal of a respective one of a pair of relays 66, 68. These relaycoils, in this example, are connected to have a common terminal 70 whichis connected through a relay energizing battery 72 to the third,grounded, slip ring 62. The relay contacts 78, 88, respectively, arenormally open and are connected, or connectable, in a singlepole,double-throw arrangement to the forward and reverse, respectively, leadsthrough a current source 90 to the terminals 92 of the spindlepositioning motor 30.

With reference to FIGURE 2, the smooth, conductive posts 92, 94 of thewire contact sensing elements 50, 52 are illustrated with the conductivewire strand 48 disposed symmetrically therebetween. Each of conductiveposts is again shown connected to its respective leads 55, 57.

In FIGURE 3 the posts 92, 94 are shown in cross section with theconducting strand 48 in elevation therebetween. The dashed lines 96indicate the position of the strand 48 when the spool 22 is disposed toofar forwardly; and the dashed lines 98 indicate its position when thespool is too far to the rear.

In operation, with the wire strand in its central, proper position asshown in FIGURES l and 2 and the solid lines of FIGURE 3, neither relayis connected to the coil energizing source 72; and both sets of relaycontacts 78, 88 remain open so that the spool positioning motor 30 isnot energized. When, however, the spool is too far forward for therequired alignment between the unwinding point 44 and the wire receivingpoint 46, the wire strand 48 may assume the position of the dashed lines96 in FIGURE 3, the conductive post 92 of the sensing element 50` isconsequently grounded causing energization of the coil of the relay 66,the contacts 88 close to connect the source 90 to the reverse lead ofthe motor 30 whereby the motor is energized and rotates the lead screw28 to cause a 4movement of the spindle carriage 26 in the -direction toremove the strand 48 from contact with the sensing element 50.

In the same manner, when the winding strand contacts the sensing element52 indicating that the spool is disposed axially too far to the rear,the lead 55 is grounded causing energization of the relay 68 whichcloses the contacts 78 to cause energization of the positioning motor inthe forward direction.

Thusly the electrical contact and positioning drive system disclosedprovides continual adjustment, as needed, of the reservoir supply spool2.2 so that the wire strand is always removed from the spool at a fixed,known angle with respect thereto. In this manner, the angular speed ofthe spool and hence the tension in the strand 48 need not undulate dueto a fluctuation in the take-off angle of wire from the spool.

Referring to FIGURE 4 an example of the invention is illustrated whichis particularly adapted for utilization with a non-conductive strand oran insulated strand. In this example a conductive switch arm wirefollower member 100 is axed at a pivot point 182 to the support member54. The pivoted switch arm member is grounded, as indicated by theconnection 104 to the winding cage structure through its connectionthereto at the pivot point 102. The end of the arm member 100 is formed,in this example, to include a strand encircling loop portion 106 at itsend opposite from the pivot point 162. For purposes of clarity, the sizeof the eye of the loop portion 106 is exaggerated and the strand isomitted from the figure. In practice, the loop portion is designed to beonly slightly larger than the strand -diameter whereby when the strandis received therethrough axial motion of the strand causes acorresponding following displacement of the arm member 10i) with aminimum of backlash or delay.

In this manner, as in the previous example, a predetermined displacementof the strand causes a grounding of a particular one of the conductiveposts 92', 94 thusly generating the control signal for moving thecarriage assembly 26 to correct the angular displacement of the unwindpoint 44 with respect to the receiving point 46.

There have thus been disclosed and described a numlber of illustrativeaspects of an example of a continuous coil Winder system which exhibitsthe advantages and achieves the objects set forth hereinabove.

What is claimed is:

1. In a winding `machine for removing, by unwinding, a strand ofmaterial from a reservoir spool thereof and winding the strand on a core`mandrel moving longitudinally through the center of said spool along apredetermined winding axis, apparatus for maintaining the angle at whichsaid strand in unwinding leaves said spool within predetermined limitswith respect to said predetermined winding axis of said spool, saidapparatus comprising:

(A) carriage means axially reciprocally movable over a distance equalapproximately to at least the length of said spool,

(1) said carriage means being adapted to receive and support said spoolin rotatable relationship about said axis;

(B) bidirectional power means lconnected to said carriage means forreciprocally moving the same in an axial direction, the sense of whichis controllable;

(C) sensing means positioned adjacent said strand adapted to determinevariants of said strand from said angle and to initiate a signalindicative of said variance and the sense thereof; and

(D) control means interconnecting said sensing means and said powermeans for causing said power means to move said carriage meansresponsive to said signal in a direction to return said angle withrespect to said variance thereof to within said predetermined limits.

2. Apparatus as defined in claim 1 wherein said carriage means includesa hollow spindle member through which said mandrel core passes and uponwhich said spool is received, an axially translatable support memberupon which said spindle member is carried, and drive means connectedbetween said yaxially translatable support member and said power meansfor reciprocally moving said axially translatable support member.

3. Apparatus as defined in claim 1 wherein said strand is electricallyconductive material and in which said sensing means is a pair ofelectrical conductors, one positioned on each side of said strandwhereby a iirst signal is generated when said strand varies from saidangle in a iirst direction and a second signal is generated when saidstrand varies from said angle in the opposite direction.

d. Apparatus as defined in claim 1 which further includes:

(A) rotatable Winding cage means disposed concentrically about said axisand having strand unwinding means carried thereby for said removing ofsaid strand from said spool, said unwinding means defining a strandreceiving point between which and the strand unwind point on saidreservoir spool, the unwinding strand is suspended;

(B) said sensing means comprising a pair of conductive members insulatedfrom each other carried by said winding cage means contiguously to saidstrand receiving point and disposed effectively forwardly and rearwardlyin relation to said suspended strand whereby when said angle is withinsaid predetermined limits-thc strand is disposed non-contactinglybetween said conductive members and is disposed in contact with apredetermined one thereof when said unwind point of said reservoir spoolis axially displaced in a predetermined sense causing said angle to benot within said predetermined limits, and is in Contact with the otherof said conductive members when said unwind point is displaced in theopposite sense to cause said angle to be not Within said predeterminedlimits.

5. Apparatus as defined in claim 4 in which said strand is conductiveand which further includes electrical connection means for coupling eachof said conductive members and said conductive strand to said controlmeans.

6. Apparatus as defined in claim 4 in which said strand receiving pointof said strand unwind means is disposed in axial alignment with theaxial midpoint between said forwardly and rearwardly disposed conductivemembers, and said predetermined limits of said angle straddle 7.Apparatus as defined in claim 1 in which said bidirectional power meanscomprises a reversible motor and an elongate lead screw coupledmechanically between said motor and said carriage means.

8. In the process of removing, by unwinding, a conductive strand from arotatable, axially translatable spool reservoir thereof and winding thestrand upon a core mandrel moving longitudinally through the center yofthe spool along a predetermined winding axis, the method for maintainingthe angle with respect to said winding axis at which said strand inunwinding leaves said spool within predetermined limits comprising thesteps of:

(A) passing said conductive strand between an insulated pair ofeffectively rearwardly and forwardly spaced conductors as it leaves saidspool during said unwinding whereby when said angle is within saidpredetermined limits, said strand does not contact either of saidconductors and when said angle is not within said limits in onedirection, one of said conductors is contacted by said conductivestrand, and when said angle is not within said limits in the otherdirection the other of said conductors is contacted by said conductivestrand;

(B) generating a correction electrical signal indicative of which of andwhen said strand is in Contact with either of said conductors;

(C) utilizing said correction electrical signal to translate axiallysaid spool reservoir in the proper sense of axial direction as needed tomaintain said angle within said predetermined limits.

9. The invention as defined in claim 1 in which said sensing meansincludes a pair of axially spaced sensing elements and a strandfollowing member adapted to receive said strand and move axiallytherewith toward different ones of said sensing elements in accordancewith the latters angular excursions, in different senses, from saidpredetermined limits.

10. Apparatus as defined in claim 1 wherein said sensing means includesa pair of axially spaced electrical conductors and a strand followerconductive member disposed pivotally therebetween for engaging saidstrand and being of the character to Contact one of said electricalconductors when said angle varies from said predetermined limits in oneaxial sense and to contact the other of said electrical conductors whensaid angle varies from said predetermined limits in the opposite axialsense.

References Cited UNITED STATES PATENTS 2,989,256 6/ 1961 Lee 242-93,031,153 4/ 1962 Attwood et al 242-9 XR 3,236,039 2/ 1966 Fletcher etal. 57-18 3,304,705 2/1967 Rathje et al. 57-18 BILLY S. TAYLOR, PrimaryExaminer.

